Radio frequency sputter deposition of si02 films at high rate

Abstract

SiO2 films have been deposited by rf sputtering in a conventional tuned substrate rf diode system at 40.68 MHz. Deposition rates as high as 2690 Å/min were achieved on a single 125-mm-diam silicon substrate, as compared to a typical rate of 250 Å/min for large manufacturing batch tools. Substrates were cooled using gas conduction, to limit temperatures to below 150°C. These films were nonabsorbing and had stress and refractive indexes in the normal range for conventionally sputtered films, without the need for added oxygen to the argon gas. Temperatures were measured using a Luxtron Fluoroptic Thermometer. Deposition rates were compared to those predicted from a simple computer model, of the system, using published sputter-yield data and measured electrode voltages. Good agreement was obtained using a weak plasma approximation for the sheath voltage at the system wall. Films were deposited at low and high (planarizing) resputtering conditions using simple substrate tuning adjustment. © 1987, American Vacuum Society. All rights reserved.